Question. I know that I can set different "Accounts receivable" sub accounts through "control accounts" but in this way the account receivable is linked to a particular client. I need to have different "Accounts receivable" and every time I issue an invoice the possibility to choose the sub account. Is it possible?

If one customer can be under multiple control accounts, then customer has really multiple separate accounts therefore customer should be created multiple times.

This is the same when people want select currency on invoice (rather than for customer). If you are issuing one customer invoices in multiple currencies, then customer has really multiple accounts with you which are tracked separately.